This invention relates to engine fuel injectors and, more particularly, to a method for locating an injector ball valve guide during or prior to crimping of the valve seat and guide in a valve body.
It is known in the art relating to solenoid actuated engine fuel injectors to provide an armature fixed to a valve ball to act as a solenoid actuated valve element. The valve ball is seatable on a valve seat and guided by a disk guide, the guide and valve seat being mounted in a recess of a valve body and secured therein by crimping an edge of the recess. The guide is provided to maintain the valve ball in close alignment with the valve seat when the valve is open so that uniform fuel flow around the valve will be promoted and closure of the valve will require a minimum of sliding motion on the seat with a minimum of closing time. Typically, aligning the valve guide with the valve seat during assembly and crimping has involved excessively costly and complicated alignment methods.
The present invention provides a method for assembly of a valve guide disk and a valve seat in an injector valve body, wherein the guide disk has a guide opening for guiding a valve ball with slight clearance and the valve seat has a ball seat facing the guide disk in assembly for engagement by the valve ball in a valve closed position. An exemplary form of the method includes:
providing a valve body having a through passage with inlet and outlet ends and an enlarged recess at the outlet end for receiving a valve guide disk and a valve seat, the recess having a crimpable edge;
inserting a locating tool from the inlet end into the through passage of the valve body, the locating tool having an oversize locating ball receivable within the guide opening with minimal clearance;
inserting a guide disk and a valve seat into the recess with the guide opening engaging the locating ball, the guide disk engaging an end surface of the recess and the valve seat engaging a flat surface of the guide disk;
seating the locating ball on the valve seat, thereby aligning the guide opening of the guide disk with the ball seat of the valve seat;
loading the valve seat and guide disk against the end surface of the ecess;
concurrently crimping the edge of the recess against the valve seat to maintain the valve seat and guide disk in their aligned positions in the recess; and
removing the locating tool from the guide opening for assembly of the resulting valve body assembly into a fuel injector.
In a variation of the above method, the guide disk and valve seat are aligned by the oversized ball and then tack welded or otherwise fixed together. The result is an aligned subassembly for subsequent installation into a fuel injector by conventional assembly processes.
These and other features and advantages of the invention will be more fully understood from the following description of certain specific embodiments of the invention taken together with the accompanying drawings.